 /*******************************************************************************
  * Copyright (c) 2006, 2007 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.core.internal.databinding.observable.tree;

 /**
  * Context sensitive children update request for a parent and subrange of its
  * children.
  *
  * @since 3.3
  */
 public interface IChildrenUpdate extends IViewerUpdate {

     /**
      * Returns the parent element that children are being requested for
      * as a tree path. An empty path identifies the root element.
      *
      * @return parent element as a tree path
      */
     public TreePath getParent();
     
     /**
      * Returns the offset at which children have been requested for. This is
      * the index of the first child being requested.
      *
      * @return offset at which children have been requested for
      */
     public int getOffset();
     
     /**
      * Returns the number of children requested.
      *
      * @return number of children requested
      */
     public int getLength();
     
     /**
      * Sets the child for this request's parent at the given offset.
      *
      * @param child child
      * @param index child offset
      *
      * TODO: what to do with <code>null</code>
      */
     public void setChild(Object child, int index);
 }

